Infinite variable slide motion for a mechanical power press

ABSTRACT

An infinite variable slide motion for a mechanical power press is achieved by use of a differential located on the press drive system. Differential movement means are employed to rotate the differential relative to the drive system so that the output of the differential may be increased or decreased relative to the drive system.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the invention

[0002] The present invention relates to mechanical presses, and, moreparticularly, to a variable slide motion adjustment apparatus and methodfor changing the motion versus crankshaft angle curve of the pressslide.

[0003] 2. Description of the related art

[0004] Mechanical presses, for example, stamping presses and drawingpresses, comprise a frame having a crown and bed. A slide is supportedwithin a frame for motion toward and away from the bed. The slide isdriven by a crankshaft having a connecting arm connected to the slide.

[0005] Such mechanical presses are widely used for stamping and drawingoperations and vary substantially in size and available tonnagedepending upon the intent of use.

[0006] After manufacturing of a mechanical press, the only way to changethe slide motion or the usual slider crank motion of the slide, was tosubstitute new parts and particular sizes and gearing of the press.Additionally, a necessity was the use of a wrench or other hand tools tochange particular settings on the apparatus thereof. A benefit in sometypes of press room operations would be the ability to change the slidercrank motion to vary the speed and dwelling of the slide without suchmanual adjustments.

[0007] Of interest, in some mechanical presses, is that there areportions of the slide which may be actuated by a hydraulic cylinderhydraulic pressure in the same rectilinear direction as slide movement,so therefore the bottom of the slide may be controlled in an additionalupward or downward direction during slide reciprocation. Such structurenecessitates additional parts such as the hydraulic cylinders orhydraulic pressure application means, along with the various plumbingand controls that necessarily reciprocate with the slide. Suchadditional mass on the slide may cause problems in press balance duringoperation.

[0008] What is needed in the art is the ability to mechanically alterthe slider crank motion of the slide without the use of wrenched or handtools to maintain mechanical connections between all of the movingparts.

SUMMARY OF THE INVENTION

[0009] The present invention is directed to improve mechanical pressslide motion control by creating an apparatus and method for allowingmechanical control of the slide motion versus crankshaft angle curve,thereby altering the speed position and dwell of the slide duringoperation.

[0010] The present invention provides an infinite variable slide motioncontrol apparatus utilizing a differential disposed between thedriveshaft and connection arms of the slide. Such a differential iscontrolled or adjusted by links connecting such differential to otheroperating gears. By varying positions of the links connected to thedifferential and their particular orientation relative to the gearing,the effective link length is adjusted, thereby changing the type ofslide motion. Changes in slide motion may be used to obtain the bestperformance of a particular die used in production with the workpieceson the press. Such effective link length adjustment is controlled by useof a hydraulic motor within an encoder giving a pulse count of theposition of the link being adjusted. By determining the effectivelocation of the link to the associated gearing and differential controlof the press slide, an effective press slide curve is created.

[0011] The invention, in one form thereof, comprises a mechanical pressincluding a frame and bed connected together with a slide connected withthe frame for reciprocating motion opposing the bed. In the preferredembodiment, the clutch is still engaged as conventionally utilized inthe flywheel with the energy from the flywheel being transmitted to theslide through a driveshaft, main gears through a controlled differentialto a crankshaft and slide connection arms. Differential mechanismoperation is controlled via the position of a link and link spiderarrangement connected either to the main gear of a press or to anauxiliary drive gear.

[0012] The invention, in another form thereof, includes a hydrauliccylinder, screw adjustment or other means to vary the effective positionand/or length of a link or link spider connected to one of the main gearor drive gear of the press. Such changes in relative position of thelink can cause the differential in a particular application, to controlmotion of the other operating portions of the press.

[0013] An advantage of the infinite variable slide motion system of thepresent invention is that now mechanical presses may control the motionversus crankshaft angle curve, with variable alternate slide motioncurves as needed for particular press or drawing operations. Ofparticular interest is the ability to mechanically change the dwell ofthe press slide to maintain it for particular periods of time andcrankshaft or driveshaft rotation.

[0014] Another advantage of the present invention is the ability toutilize a differential between the main gear and eccentric portions ofthe crankshaft, thereby obtaining particular control of the powerapplied thereto.

[0015] A further advantage of the invention is the ability to create aslide motion different from the normal slider crank motion to increasethe dwell of the slide on the bottom for upwards of 25°±15°.

[0016] Yet another advantage of the present invention is the ability ofthe clutch to maintain fully engaged and transfer energy therefrom tothe crankshaft and slide via entire mechanical connections.

[0017] Another advantage of the present invention is that the infinitevariable slide motion may be adjusted without a wrench or hand tool, butby use of a hydraulic motor controlling the effective position or lengthof the control links utilized.

[0018] Yet another advantage of the present invention is that the systemnow allows dies and tooling to tap or draw at 90° from the bed duringthe vastly extended slide dwell period.

[0019] Still another advantage of the present invention is the creationof a substantially constant slide and die velocity during the bottom 25percent of slide stroke.

[0020] A further advantage of the present invention is the ability towithstand overload hits without breaking the links between the slide andcrankshaft. Stamping presses may take tremendous overload due to itemsleft in the presses, and for other reasons. A conventional press withcrankshaft connection slide can withstand such load, but presses withlinks between the crankshaft and slide for adjusting stroke have hadtrouble withstanding such severe overloads.

[0021] Another advantage of the present invention is on a high speedpress a dynamic balancer may be adjusted at the same time as the slidemotion is adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above-mentioned and other features and advantages of thisinvention, and the manner of attaining them, will become more apparentand the invention will be better understood by reference to thefollowing description of an embodiment of the invention taken inconjunction with the accompanying drawings, wherein:

[0023]FIG. 1 is a elevational view of a mechanical press incorporatingthe infinite variable slide motion system of the present invention;

[0024]FIG. 2 is a graph showing a motion versus crankshaft angle curvefor both a conventional press (dashed line) and one of the presentinvention (solid line);

[0025]FIG. 3 is an end view of a portion of the mechanical press shownin FIG. 1;

[0026]FIG. 4 is a top and side view of a portion of the press shown inFIG. 1;

[0027]FIG. 5 is an engaged view of an embodiment of the drive mechanismof the present invention;

[0028]FIG. 6 is a diagram of the main gear, link pivot connection of oneform of the invention;

[0029]FIG. 7 is a section view of an embodiment of the differentialutilized in the present invention;

[0030]FIG. 8 illustrates means for effective link position lengthadjustment utilizing a hydraulic motor;

[0031]FIG. 9 is a section view of an alternate embodiment of the presentinvention utilizing planetary gears and connection of the differentialto the press driveshaft; and

[0032]FIG. 10 is a diagram of the main gear link pivot connectionincluding hydraulic cylinder length adjustment means for both the linkmain gear and the link spider.

[0033] Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification set out hereinillustrates one preferred embodiment of the invention, in one form, andsuch exemplification is not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Referring now to the drawings and particularly to FIG. 1, thereis shown a mechanical press 10 comprising a crown 12, a bed portion 54having a bolster assembly 16 connected thereto, and uprights 52connecting crown portion 12 to bed portion 54.

[0035] Uprights 52 are connected to or integral with the underside of 10crown 12 and the upper side of bed 54. Die 53 is located between slide51 and bed 54. Tie rods (not shown) extend through crown 12, uprights52, and bed portion 54 and are attached on each end with a tie rod (notshown).

[0036] A drive mechanism, such as a press drive motor 43, is attached tocrown 12 of the press and connected by belts 42 to a flywheel 141. Suchflywheel 141 is thereby connected to a clutch/brake mechanism 44 thatmay transmit rotational energy to press driveshaft 45.

[0037] As shown in FIG. 1, press driveshaft 45 on opposite ends 20includes a pinion gear 6 engaging a main gear 49. Main gear 49 isconnected to crankshaft 2 on which particular connections 50 attach toslide 51. Dies 53 are attached one each to both the slide 51 and bolsterassembly 16.

[0038] The mechanical power press, as shown in FIG. 1, includes aneccentric (not shown) on crankshaft 2. A typical connection of theeccentric between the connection 50 and crankshaft 2 will create a slidemotion curve as shown in FIG. 2 dashed line. This type of slide orcrankshaft motion is similar to the majority of all mechanical presses.

[0039]FIG. 3 shows one view of the present invention, more particularly,the end view of the mechanical press of FIG. 1, in which the main gear49 is connected by a link 69 to pivot link 71. Pivot link 71 isconnected by a link spider 70 to differential 84. FIG. 4 shows a top andside view of the connection.

[0040]FIG. 5 shows an enlarged view of one particular drive mechanism ofthe present invention, in which the flywheel 141 is connected to aclutch 44 onto the driveshaft 5. A pinion 6 is thereby connected androtates main gear 49.

[0041]FIG. 10 illustrates link main gear length adjustment means 28.Link main gear length adjustment means 28 can be, for example, ahydraulic cylinder. FIG. 6 also illustrates link spider lengthadjustment means 26, which can be, for example, a hydraulic cylinder.

[0042] The main gear 49 is fastened by bolt 61A to the input gear 20differential 60 as shown in FIG. 5 and is turned at a constant speed bypinion 6. The main gear 49 and input gear differential 60 are supportedand rotate on the crankshaft bushing 65. The input gear differential 60drives at least one pinion differential 61, which rotates on a shaft 63Aon the spider differential 63. The spider differential 63 controls theshaft 63A through pinions 61. Spider differential 63 is controlled bylink spider 70. Link spider 70 controls rotation of spider differential63 about crankshaft 2. Pinion differential 61 drives gear outputdifferential 62.

[0043] When the spider differential 63 rotation is changed, the piniondifferential 61 alters the drive of output gear differential 62 and canstop the output gear 62 if the spider differential 63 rotation cansubstantially match in the reverse direction, the input geardifferential 60. When the conditions are right, such that thedifferential slows or stops crankshaft 2 when slide 51 is down, theslide 51 may stop and dwell, thereby altering the slide motion curve.Spider differential 63 rotation combines with main gear 49, such thatthe output gear differential 62 may be faster or slower than main gear49 depending upon how spider differential 63 is controlled. Oneparticular curve is shown in FIG. 2 in which the dwell of the slide 51is maintained longer at the bottom dead center position. Other times andlocations of dwell may also be created.

[0044] In the preferred embodiment, the spider differential 63 movementis controlled by link spider 70. Link spider 70 is connected and pivotedon a link pivot 71 through a pivot pin. The link pivot 71 is pivotedabout an axis (location “z”) in FIG. 6. The link pivot 71 is pivoted bya link main gear connection 69 which is motivated (in this embodiment)by main gear 49.

[0045] The link main gear connection 69 pivots the link pivot 71 backand forth, and the link pivot 71 thereby drives link spider 70 which isfastened to spider differential 63, and thus controls spiderdifferential 63 causing a change in the output differential 62 speedwhich is fastened to crankshaft 2.

[0046]FIG. 7 shows the differential 84 of the present invention, whichincludes the spider differential housing 101. It is to this housing 101that the link spider 70 attaches.

[0047] As shown in FIG. 6, the link spider 70 connected to pivot link 71may be adjusted forward and backward by the structure shown in FIG. 8,by varying the position of link spider 70 upon link pivot 71 as shown inFIG. 6, various slide motions occur.

[0048] Link spider 70 is attached, as shown in FIG. 8, to pivot link 71by a pin link spider 80, mounted in a screw link spider 77. This screwlink spider 77 is supported on three sides by pivot link 71 and held inplace by retainer 75. The positioning of the screw link 77 is by a screwand nut link spider 78. The screw link spider 77 is part of the memberthat has the pin link spider 80 (see section B-B). A threaded portion ispositioned by rotating a nut link spider 78. This nut link spider 78includes pressurized oil to eliminate the need for a lock nut to preventundamped clearance between the thread on nut link spider 78 and screwlink spider 77. The nut link spider 78 is fastened to gear link pivot 72by bolts and the gear transmits the power to the nut link spider 78. Thegear link pivot 72 is driven by pinion link pivot 73, which is mountedonto a hydraulic motor 74. Hydraulic motor 74 obtains its hydraulicpower from a power unit (not shown).

[0049] Additionally not shown, is an encoder mounted on the pinion linkpivot 73 which feeds back pulses to a controller. A controller on thissystem controls and identifies the position of link spider 78 bycounting particular pulses or otherwise determining its location. Byrotating or operating hydraulic motor 74 which will rotate gear pivot72, an extension or contraction of the screw link spider 77 occurs. Suchextension and contraction of screw link spider 77 to which the linkspider 70 is connected thereby changes the relative location of linkspider 70 to link pivot 71. By controlling the relative position of linkspider 70 and the link pivot 71, control of the slide 51 dwell isaccomplished.

[0050] As illustrated in FIG. 10, control of the slide 51 dwell can alsoaccomplished by altering the lengths of link spider 70 or link main gear69. Length adjustment of the link spider can be accomplished byactuating link spider length adjustment means 26, for example, ahydraulic cylinder. Similarly, the length of the link main gear 69 maybe adjusted by actuating main gear length adjustment means 28, forexample, a hydraulic cylinder.

[0051] As shown in FIG. 9, an alternate embodiment is used in which thedifferential is placed on the press driveshaft 5 as opposed tocrankshaft 2. In this case, the system would need only a singledifferential versus two, such as when the press utilizes a twin drivesetup as shown in FIG. 1. This would additionally reduce costs and thepart count.

[0052] A particular problem concerning the timing of the eccentriccrankshaft 2 to the spider occurs to the spider and on the driveshaft 5differential. Additionally, there may be a requirement to reduce speed,which could be accomplished with a planetary gearing 95 between linkspider 97 and clutch 44. The ratio would change in the planetary gearingwhen the ratio between the main gear and pinion 6 are changed. There mayalso be a required speed reduction between the link spider 97 and spiderdifferential 63.

[0053] In all cases and embodiments, the differential 84 has to matchthe rotation of the crankshaft 2 or have a particular speed changedepending upon the position of crankshaft 2. In other words, after onefull rotation of the input occurs, one to the differential full rotationof the output also occurs. If the driveshaft spider differential has thecorrect change in motion, a curve as shown in FIG. 2 can be produced. Ifan adjustment of the position of the pivot on the link spider 70 ismade, an infinite variable slide curve motion between the two curves maybe made. Furthermore, this adjustment may be made via a control panel orremote personal computer. An additional benefit is that by locating thedifferential on the driveshaft as opposed to the crankshaft, a singledynamic balancer may be located between the connections and that theslide motion is changed, the balancer will be adjusted automatically ifdriven from the crankshaft. Therefore, no additional mechanisms areneeded to adjust the dynamic balancer.

[0054] While this invention has been described as having a preferreddesign, the present invention can be further modified within the spiritand scope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

What is claimed is:
 1. A press, comprising: a press drive system; and adifferential operatively connected to said drive system.
 2. The press asrecited in claim 1, wherein said press drive system comprises: a pressdrive motor; a driveshaft, said driveshaft having a first end and asecond end, said first end connected to said press motor; a pinion, saidpinion connected to said second end of said driveshaft; a main gear,said main gear driven by said pinion; and a crankshaft, said crankshafthaving a first end and a second end, said first end of said crankshaftconnected to said main gear.
 3. The press as recited in claim 2, whereinsaid differential is rotatably supported by said driveshaft.
 4. Thepress as recited in claim 2, wherein said differential is rotatablysupported by said crankshaft.
 5. The press as recited in claim 4,further comprising: differential movement means for rotating saiddifferential relative to said drive system and thereby increasing ordecreasing the output of said differential relative to said drivesystem.
 6. The press as recited in claim 5, wherein said differentialcomprises: an input gear differential, said input gear differentialaffixed to said main gear, said input gear differential rotatablysupported by said crankshaft; a pinion differential mechanically coupledto said input gear differential; a shaft, said shaft rotatablysupporting said pinion differential; a gear output differentialmechanically coupled to said pinion differential; and a differentialhousing.
 7. The press as recited in claim 6, wherein said differentialfurther comprises: a second pinion differential mechanically coupled tosaid input gear differential and to said gear output differential; and asecond shaft, said second shaft rotatably supporting said second piniondifferential.
 8. The press as recited in claim 5, wherein saiddifferential movement means comprises: a link spider pivotally connectedto said differential housing; a pivot link, having a first end and asecond end, said pivot link pivoting about said second end, said linkspider pivotally connected to said pivot link; and a link main gear,said link main gear pivotally connected to said first end of said pivotlink, said link main gear pivoting said pivot link back and forth aboutsaid second end.
 9. The press as recited in claim 8, wherein said linkmain gear is pivotally connected to said main gear.
 10. The press asrecited in claim 8, wherein said differential movement means furthercomprises: adjustment means for varying the position of said link spideralong said link pivot.
 11. The press as recited in claim 10, whereinsaid adjustment means comprises: a hydraulic motor; a pinion link pivot,said pinion link pivot mounted on said hydraulic motor; a controller forcontrolling and identifying the position of said link spider; an encoderfor feeding pulses indicative of rotations of said hydraulic motor tosaid controller; a gear link pivot driven by said pinion link pivot; anut link spider affixed to said gear link pivot; a screw link spiderthreadedly connected to said nut link spider, said screw link spidersupported on three sides by said pivot link, said nut link spiderincluding pressurized oil to prevent undamped clearance between saidscrew link spider and said nut link spider; a pin link spider forpivotally connecting said link spider to said screw link spider; and aretainer connected to said link pivot, said retainer holding said screwlink spider in place within said pivot link.
 12. The press as recited inclaim 10, wherein said link spider further comprises: link spider lengthadjustment means for varying the length of said link spider.
 13. Thepress as recited in claim 12, wherein said link spider length adjustmentmeans comprises: a hydraulic cylinder.
 14. The press as recited in claim10, wherein said link main gear further comprises: link main gear lengthadjustment means for varying the length of said link main gear.
 15. Thepress as recited in claim 14, wherein said link main gear lengthadjustment means comprises: a hydraulic cylinder.
 16. The press asrecited in claim 3, wherein said press drive system further comprises: amotor; a flywheel driven by said motor; a clutch, said clutch beingselectively engageable with said flywheel; said driveshaft affixed tosaid clutch; a pinion affixed to said driveshaft; a main gear driven bysaid pinion; and said crankshaft affixed to said main gear.
 17. Thepress as recited in claim 16, further comprising: a planetary gearing,said planetary gearing mechanically coupled to said clutch; and a linkspider, said link spider pivotally connected to said planetary gearingand to said differential.
 18. A press, comprising: a press drive system;a differential operatively connected to said drive system; anddifferential movement means for rotating said differential relative tosaid drive system and thereby increasing or decreasing the output ofsaid differential relative to said drive system.
 19. A method of varyingthe slide motion in a running mechanical press, comprising: connecting adifferential to the press drive system; and utilizing the differentialto alternatively add and subtract to the rotational velocity of thepress crankshaft relative to the rotational velocity of the press drivesystem.